Mechanically actuated hydraulic control system for pump control



MECHANICALLY ACTUATED HYDRAULIC CONTROL SYSTEI FOR PUMP CONTROL 7 FiledNov; 11, 1945 2 Sheets-Sheet 1 INVENTORS Jam/v A. mourn, BVARRENR.7"UCKER, I am 4 0M ATTORNEYS Much J. A. MULLER QETAL 2,437,115

I MECHANICALLY ACTUATED HYDRAULIC CONTROL SYSTEM PUMP CONTROL med Nov.'11,1943 2 sheets-sh t:

INVENTOPS JOIIAN A. HUUER, WARREN R. TUCKER,

, ATTORNEYS Patented Mar. 2, 1948 TUATED HYDRAULIC CONTROL SYSTEM FORPUMP CONTROL MECHANICALLY Johan A. Muller and Ohio, assignors to WarrenR. Tucker, Dayton, H-P-M Development Corporation, Wilmington, DeL, acorporation of Delaware Application November 11, 1943, Serial No.509,853

7 Claims.

This invention relates to control systems for regulating the directionof flow of hydraulic fluid to a hydraulic motor in response to movementimparted to the hydraulic motor when fluid is directed thereto bycausing initial mechanical energy to be translated into hydraulic energyfor regulating the control mechanism of the control system. 7

An objector the invention is toprovide amechanically actuated controlunit that is constructed and arranged to translate mechanical energyinto a hydraulic force for actuating a fluid flow control mechanismwhereby to regulate the direction of flow of fluid through the fluidcontrol mechanism and control the rate of flow of fluid through thefluid control mechanism when passing fluid therethrough in at least onedirection.

Another object of the invention is to provide a control mechanism inaccordance with the foregoing object wherein the fluid is directed to ahydraulic motor for operating the, same and the hydraulic motormechanically actuates the mechanism for translating the mechanicalenergy into hydraulic force whereby to control the flow controlmechanism in response to the operation of the hydraulic motor.

2 In the drawings: Figure 1 is a-schematic view of a hydraulic systemfor operating a hydraulic motor including the control mechanism of thisinvention as applied to a reversible variable delivery pump.

Figure 2 is a schematic, view of a hydraulic system for operating ahydraulic motor including the control mechanism of this inventionasapplied to a constant delivery pump.

Figure 3 is a longitudinal cross sectional view of a flow controlreversing valve associated with the constant delivery pump.

As illustrated in Figure 1 the control mechagnism is associated with areversible variable. de-

It is still another object of the invention to provide a controlmechanism and system therefor wherein the control mechanism is adaptedto regulate the fluid flow control mechanism to cause the same to reducethevolume of fluid delivered to a hydraulic motor substantially inaccordance with the movement of the'piston or the hydraulic motorwhereby to create a slow-down operation of the motor and to also storeup me,-

. chanical energy that is translated into hydraulic i power for rapidlymoving the fluid flow control mechanism to produce reversal of flow offluid through the fluid flow control mechanism.

Another object of the invention'is to provide a control system inaccordance with any of the foregoing objects wherein the source ofhydraulic fluid under pressure for operating the hydraulic motor is areversible variable delivery pump.

Another object of the invention is to provide a control system inaccordance with any of the foregoing objects wherein the source ofhydraulic fluid under pressure for operating the hydraulic motor is aconstant delivery pump having a flow control reversing valve associatedtherewith. 1

Further objects and advantages will become apparent from the drawingsand the followingdescription.

ends of the cause delivery of fluid under conduit l5 orl6, accordingly.

livery pump ID that delivers fluid under pressure toa double-actinghydraulic motor II for operating the same. The reversible variabledelivery pumpill may be of any of the conventional forms of suchpumpswherein there is provided a plurality of radially disposedpiston-cylinder assemblies thatrotate about a. common axis and areadapted to be shifted eccentrically relative to the driving axis of thepump whereby to discharge fluid under pressure from'the pump. Thepiston-cylinder assemblies are usually carried with-, in ashift ring 12whereby to shift the eccentric-- ity between the axis of thepiston-cylinder assemblies and the drive axis of the pump so thatthe-pump will deliver .fiuid through its service connections in eitherdirection or may stand on neutral with no delivery of pressure fluid ineither direction. Such reversible variable delivery pumps are well-knownin the art and it is not deemed necessary to describe the same further.The reversible variable delivery pump I0 is provided with the serviceconnections l3 and H to which conduits I 5 and I6 are connected. Theconduits I 5 and I6 are connected to opposite hydraulic motor H fordelivering flu'd under pressure'to either end of the hydraulic otor I Iin accordance with the position of the shift ring I! of the pump Ill onone side of the driving center of the. pump or the other to causedischarge of fluid under pressure to either of the pump i 0 is engagedby a shift rod l1 thatienters a spring cage l8 having a compressionspring l9 therein positioned between a collar 20 carried on the shiftrod I! and an end cap 2! cage l8. shift ring The shift ring lz Thespring I9 continuously urges the l2 in a leftward direction whereby topressure through the conduit I5.

' The spring I 9 is opposed by means of a pisclosing the end of thespring shoulder 40 on the rod tion between the chamber 48 ton 22 that isreciprocable in the cylinder 23, the piston 22 engaging the shift ringl2 to cause the same to move in a rightward direction against the springl9 when a fluid under pressure is admitted into the chamber 24 providedbetween the head of the piston and the end wall 25 of the cylinder 23.

The hydraulic motor consists of a cylinder 26 having a plunger 21therein that carries the piston 28. The plunger 21 extends through theend wall 29 of the cylinder 26 to perform any desired work operation.

A make-up valve 30 is connected in the conduit 3| that connects betweenopposite ends of the cylinder 26 for supplying fluid from the reservoir32 to the pump l9 whereby to provide means for supplying additionalfluid into the chamber 33 of the cylinder 26 when the pump is deliveringinto the chamber 33. The makeup valve 30 is of the conventional shuttlevalve construction well-known in the art and used for this purpose.

The control for the reversible variable delivery pump III to change thedirection of delivery from the pump and to regulate the rate ofdischarge includes a cylinder body35 having a longitudinal bore 36therein that is closure cap 31 threaded upon the body 35. A plunger rod38 extends through the closure cap 31 and has a collar 39 carriedthereon against a 33. The opposite end of engaged by a collar 42.extends between the the rod 38 has a head 4 A compression spring 43collars 39 and 42 to" normally retain these collars against the shoulderand the head 4|, respectively. The assembly just referred to isreciprocable in the cylinder bore 36 for purposes to be hereinafterdescribed.

The projecting end of the rod 38 has a roller 44 carried thereon thatengages a cam bar 45 that is actuated by the plunger 21 of the hydraulicmotor The cam bar 45 may be carried directly by the plunger 21 or beactuated thereby through a suitable linkage system so that reciprocalmovement oi'the cam bar 45 represents similar reciprocal movement of theplunger 21 of the hydraulic motor The cylinder body 35 has a secondlongitudinal bore 46 extending coaxially from the bore 36 in which apiston 41 reciprocates. The piston 41 has the lower end thereof restingupon the collar 42 carried by the plunger rod 38 while the upper end ofthe piston 41 forms one wall of a chamber 48 in the cylinder bore 46.The piston 41 has a .counterbore 49 that is connected with the bore 36through a passage 59 provided in the wall of the cylinder 41 to permitentry of fluid under pressure for operating the piston in a manner thatwill be hereinafter described. A reservoir is positioned around the endoi' the cylinder body 35 and is connected with the chamber 48transmitting means.

closed on one end by a through the valve by means of the control handle63. The choke valve 62 is adapted to be adjusted so as .to restrict theflow of fluid from the chamber 4B in the control member 60 to thechamber 24 in the pump control cylinder 23 in a manner to be hereinafterdescribed. These connections 48, 62, 6| and 24 constitute a regulatedforce A three-way valve 65 is placed in a conduit 66 that connects'thecylinder bore 36 of the control member 60 with the service conduit 5 forthe pump l0, so that when the valve passage 61 is in the positionillustrated in Figure 1 the cylinder bore 36 of the control member 60 isopened to exhaust by way of the makeup valve 30 or to the suction'sideoi! the pump l9 by way of conduit I6, the conduit |5 at this time beingthe discharge conduit from the pump l9 for reasons which will becomemore apparent hereinafter. A second conduit 68 connects the valvepassage 61 with the reservoir 32 through a passage 16. when the rotor 69of the valve 65 has been rotated to the position wherein the passage 16is in alignment with the conduit 68 to connect the conduit 66 with thereservoir 32 for reasons hereinafter described.

The valve 65 is operated by means of a lever 10 that extends from therotor 69 into engagement with a rod 1|, suitable collars 12 beingprovided on opposite sides of the arm 19 for oscillating the same uponreciprocation of the rod 1|. A

tension spring leftward direction, that the valve passage into thisposition.

The rod 1| extends through an arm 14 that projects from the plunger 21of the hydraulic moby means of a conduit passage 52. This passage 52 isso positioned that it is in open communicaand the reservoir 5| only whenthe piston 41 is in its completely downward position as illustrated inFigure 1. The reservoir 5| is provided with a body of fluid formaintaining the chamber 48 filled under the conditions of operation.

The chamber 48 of the control member 60 is connected to the chamber 24of the pump control cylinder 23 by means of a conduit 6| that has anadjustable choke valve 62 positioned therein. The choke valve 62 may bemanually adjusted to vary the opening of the passage forward stroke. Thepump tor The rod 1| has a collar 15 thereon that is engaged by the arm14 near the end of the retraction stroke, or rightward stroke, of theplunger 21 so as to shift the rotor 69 of the valve 65 to align thepassage 16 with the conduit 68 and thereby exhaust the chamber bore 36of the control member 69.

When the hydraulic motor II is on iforwart stroke, that is moving to theleft, the pump i0 is delivering fluid under pressure into the condui1 l5and-is withdrawing fluid from the hydraulir motor through the conduitI6, additional fluic required for filling the chamber 33 of thehydraulic motor being drawn in through the make up valve 30. The valve65 and the control mem' ber 60 are in the position as illustrated in Figure 1 when the hydraulic motor is thus on it It) will be deliverinl fullcapacity into the conduit I5, thus the shif ring I2 will have moved thepumping mechanisn to the left so as to cause the same to deliver th,full capacity, the spring |9 having caused thi movement the passage 52between the chambr 48 and the reservoir 5| will be closed by the bee ofthe piston 41 thus trapping liquid in the char: ber 48, the conduit 6|and the chamber- 24 of ti control cylinder 23. The liquid trapped in tlchamber 48 will thus be transferred from tl chamber 48' to the chamber24 of the contr cylinder 23 causing the piston 22 to be moved arightward: direction.andthus -shltting the shirt ring'l21oi' the pump xill toward neutral; or no- Theliquid. in the chamber 482: 6 Ii thus?provides a hydraulic the: piston" 22 and shifting fthe.

delivery .positi'ona'r and the conduit' force for moving: pump l0.-

that'the rate of. flow through the choke valve is the same as the rateat. which'liquid is discharged from the chamber by the upward movementof the piston 41 wherebyu-the control piston 22 for the pump lll iscaused to substantially follow the actuating movement-of follow-themovement of'the plunger 21 of .the 'hydraulic motor I I;

the conduit l whereby therplungenfl of the hydraulic motor II The choke.valve. 62 "is. preferably adjusted so thecam bar 45 and thus By thisarrangement the pump is caused to deliveriless fluid-underpressure into.

is'placed on a forwardv slow-.--

retain. the

down stroke. The point'of maximum slow-down,

or position: of the plungerv 21in its forward move ment at'the positionofiimaximum slow-down canv be calculated by'the-ppsitionof the juncturebetween the cam rise. surface45a and the camrland .second .cam. surface450 :can/ be:

4517. If desireda provided on the camxbarqfiw to produce an: additionalslow-down neutral position.

If the liquid is discharged from the chamber 48 of. the controlmember 60at the'same rate that it is received into the chamber 24 of. thecontrol.cylinder 23, it :will: bequite apparent that. when action: upon thehydraulic mo- 1 tor H by shiftingthe pump. Illv further. toward:

the pump. Hlreaches neutral positionwthere: will..

delivery 1 of pressure fluidthrough thus'stopping-the the pump. I 0'would never position.

be no further the conduit: l5 hydraulic motor 1| I and gointo reverse.delivery To overcome, this condition "the cam. rise.:- dzis' provided onthe cam bar 45 that {is substantially steeper than the'cam rise-'45a..When. the cam:

' 44 the plunger. 3821s 7 rapid rate than" liquid? can be displacedfromthe'chamber 4'8 oftheiconithe choke valve 62,- whereby the head 4 Iof the .plunger 38 :will. move upwardly into the recess49- 'in the lpiston: 41- and v the spring.'-43*will thereby becompressed to: provideastoring-0f mechanicalenergy inthe spring of the piston 41 even:

rise 45d strikes theroller moved upwardlyat a more trol member 601through for continuing movement. though theplunger.38-'-='is=stationary.-. It :willi'be apparent that if the. head'ofxthe plunger 41' is removed from contact. with the collar 42' thatthe compressional the spring-43will movethepiston' 41 into the chamber48 and therebydisplace liq.-

uid from the: chamber "48 'throughr the choke valve 82 intothechamber-2'4- of-the control cylinder: 23 collar 42 again1..engagesthe head. onit'he'end of'the plungerrodzil; The piston 22 willthereby-be 'movedtowardithe-v until such time as the.

right to shift the pump HI. through; the neutral; reverse delivery:positionposition. and: into the sothat fluidjundernpressure'will then:be dis.-

charged through the-conduit; |=6 into the. pushback side'rof thehydraulic motor ll.

When the pump l0 begins delivery or fluid; un der pressure intothe...conduit IS the piston' 28 6:. I pump... lotion; therevorsedeliverypost-- time I The plungerllctthehydraulic motor II can now. move in. a.rlghtwardzdirection. on its return ..s.troke;-;thewvalve:Niremaining.in; its-position; as illustrated-Limfigure- 1-. When. the plunger; 21apaproaches theiend-riol' its 74-; attachedlto the. plunger.- collar."carried on the .rod H; and. move the rod." in a rightward. directionto-rotate. the valve -65iin .a, counterclockwise direction and therebybringgthe-passages 16. into communica: tion vwith the conduit; whereuponpressure is released from; the; conduit 66 'andthe chamber 3.6; in, thecontrol. member This release of pressure upon. the. piston 41' in thecontrol memthereby, displace liquid fromthe. chamber a 24 in the.control'cylinder- 23 into the chamber 48 of thecontrol member. 60,thereby placing'the pump l-llonaforward delivery position so that fluidunder pressurewill: again bedischarged into the conduit I 5;. As soon asthe plunger 21 of the *hydraulicmotor H. has advanced apart of itsstroke, the valve' will be rotated in a. clockwise direction by means ofthe spring 13 to-again place it. in the position, as illustrated inFigure 1, for action to accomplish another return stroke as heretoforedescribed.

- From, the foregoing-description it will now become apparent thatby-this invention mechanical power is" usedf'for. hydraulically shiftingapump from one; delivery" position toward another and-mechanicalenergy-is; stored for shifting the pump;- through a; livery position:to; another.

While the invention heretofore described. has beenwin: combination. witha reversible variable delivery pump,- the invention is applicable foru'sewith auhidirectional'delivery pump that has valve means'associatedtherewith for shifting the direction. oiiflow offiuid. from the pump toopposite-:endsv offer hydraulic. motor. In Figure .2 there isillustrated-such a system having the valve element. illustrated inFigure 3"and in. referring.

" to the system, illustrated inFlgure 2, the same numerals will.beusedas referred to in Figure 1 of the hydraulic 'motor-l'l will bemoved-in a rightward direction; carrying with it the cam bar. 45. Theplunger38willthus follow thecam bar- 45 and move outwardly away-from thepiston 41. However. when pressure fiuid'wassupplied to the: conduit I 6,pressure fluidalso passed through the conduit GG-into thechamb'er 35'and entered. thechamber 49' in the piston 41 'totherebyhold' the piston.41 inits. upwardly disposedposition to valvemember' foridenticalzelements' are raised by 100;

In: this. arrangementthere isprovided a uniexcept. that the numeralsdirectional delivery pump. havingan inlet con.-

duit' "connected tothe. reservoir I 32? and a pressure dischargeconduit- 82 that delivers into the reversing valve .83. A; pressure.relief. valve 84 connects the pressure delivery side .82 with theinlet-sided! to: prevent anabnormal rise-in the pressure-deliveredtromthepump.

The reversingvalve 83' is provided with exhaust: lines 85 and'liionoppositeends thereof that; communicate with: the reservoir I32.

lines, l1 and 88 that ends ofz'the hydraulic. 88' being-connected. tovconduit I66;

Asv illustrated in Figure 3 the reversing. valve 83 is provided-with acylinderbore-l! that carries 9, having the spools 9| and 92 thereoh. Thevalve rod- 93extends through the end ofithe casing of the reversingvalve 83 and carries a piston 94 reciprocable in' the cylinder 95;Acompresslon spring, continuously urges the piston 94. in:axleftwardzdirection to normally are. connected to opposite motor II I;the service line neutral" position from one dethe .valve .165- throughthe disclosed in Figure 2 herein is illustrated by a the spirit of theposition the valve spools 9| and 92 as illustrated,

in full lines in the drawing in Figure 3.

The operation of the reversing valve 83 will now be apparent whereindelivery through the conduit 82, when the valve is positioned asillustrated in Figure 3, will cause delivery into the service line .81andthus place the hydraulic motor III on a forward or advancing stroke.The operation of rise cam surface 5d engages the roller I44 the controlmember I60 will actuate the piston 94 of the reversing valve 83 to shiftthe valve through the position wherein both service ports 81 and 88 areclosed by the spools 9| and 92 into the position illustrated in dottedlines so that the pump 80 will now deliver from the discharge conduit 82into the service line 88.

As soon as pressure is applied to the service line 88, pressure is alsoapplied to the conduit I66 and thereby holds the piston 0f the controlmember 60 in position to retain the reversing valve 83 in the dotted-line position until the pressure is relieved in the service line 88 andthe conduit I66 by operation of the valve I65 in the manner heretoforedescribed.

It will therefore be apparent that the system will function inidentically the same manner as the system disclosed in Figure 1. V

While the invention disclosed and described preferred form of theinvention, yet it is to be understood that the apparatus disclosed iscapable of mechanical modification, or alteration without departing frominvention, and that such modiflcations as fall within the scope of theappended claims are intended to be included herein.

Having thus fully described our invention what We claim as new anddesire to secure by Letters Patentis:

1. A fluid flow controlling apparatus in a hydraulic actuating systemthat includes, means providing a source of fluid under pressure foractuating a fluid motor operably connected therewith and including meansreversing the direction of flow of fluid under pressure-between thesource and the fluid motor having two definite positions for' causingdelivery of pressure fluid from said source in either of two directionsand which passes through a neutral or non-delivery position whenshifting the flow of fluid from one direction to the other, mechanicallyactuatcdmeans operably connected with said fluid motor for actuationthereby including means for mechanically storing energy upon actuationof said mechanical means, means for producing hydraulic pressureoperably connected to said mechanical means and hydraulically connectedwith said fluid flow reversing means for hydraulically operating thesame to shift said flow reversing means from one of said positions tothe other through the neutral post-- tion upon release of energymechanically stored in said mechanical means, and means hydraulicallyconnecting said means for producing hydraulic pressure with said sourceof fluid pressure on the discharge'side thereof after the fluid means inone of two positions flow therethrough has been reversed upon actuationof said reversing means by said mechanical means whereby to retain saidmeans for producing hydraulic pressure in operative position to retainsaid source of fluid pressure on delivery in the direction of flow ascaused by operation of said mechanical means.

2. A fluid flow controlling apparatus in a hydraulic actuating systemthat includes, means providing a source of fluid under pressure foractuating a fluid motor operably connected therewith and including meansreversing the direction of flow of fluid under pressure between thesource and the fluid motor having two deflnite positions for causingdelivery of pressure fluid from said source in either of two directionsand which passes through a neutral or non-delivery position when,shifting the flow of fluid from one direction to the other, mechanicallyactuated means operably connected with said fluid motor for actuationthereby including means for mechanically storing energy upon actuationof said mechanical means, means for producing hydraulic pressureoperably connected to said mechanical means and hydraulically connectedwith said fluid flow reversing means for hydraulically operating thesame to shift said flow reversing means from one of said positions tothe other through the neutral position upon release of energymechanically stored in said mechanical means, means hydraulicallyconnecting said means for producing hydraulic pressure'with said soureof fluid pressure on the discharge side thereof after the fluid flowtherethrough has been reversed upon actuation of said reversing means bysaid mechanical means whereby to retain said means for producinghydraulic pressure in operative position to retain said source of fluidpressure on delivery in the direction of flow as caused by operation ofsaid mechanical means, and means operably connected to said fluid motorfor releasing pressure from said last mentioned hydraulic connection inresponse to a predetermined position of said fluid motor whereby topermit said fluid flow reversing means to reverse delivery from saidfluid sourceand thereby direct fluid under pressure in the oppositedirection to said fluid motor.

3. A fluid flow controlling apparatus in a hydraulic actuating systemthat includes, means providing a source of fluid under pressure foractuating a fluid motor operably connected therewith and including meansreversing the direction of flow of fluid under pressure between thesource and the fluid motor having means for normally positioning saidflow reversing to normally cause said source to deliver in one directionand hydraulically actuated means opposing the same to shift'the flowreversing means through a neutral or non-delivery position into a secondposition for reversing the flow of fluid from said source, mechanicallyactuated means operably connected to said fluid motor for actuationthereby having means to directly transmit motion ,of said fluid motorand resilient means for mechanically storing energy upon motion thereofby said fluid motor, means for hydraulically producing pressureoperablyconnected to said mechanical means for actuation thereby andhydraulically connected to said hydraulic actuating means of said flowreversing means, and fluid throttle control means in said last mentionedhydraulic connection to regulate the rate of transfer of fluid from saidmeans for producing hydraulic presfrom the means producing hydraulicpressure through said throttle control means causes said resilient meansto store energy mechanically to continue transfer of fluid from saidmeans producing hydraulic pressure to said hydraulic actuating means forsaid flow reversing means and shift the same through neutral position torenon-delivery position into a second position for reversing the .flowof fluid from said source,

verse flow position after the actuation of said mechanical means hasstopped and energy is re leased by said resilient means.

4. A fluid flow controlling apparatus in a hydraulic actuating systemthat includes, means providing a source of fluid under pressure foractuating a fluid motor operably connected therewith and including meansreversing the direction of flow of fluid under pressure between thesource and the fluid motor having means for normally positioning saidflow reversing means in one of two positions to normally cause saidsource to deliver in one direction and hydraulically actuated meansopposing the same to shift the flow reversing means through a neutral ornon-delivery position into a second position for reversing the flow offluid from said source, mechanically actuated means operably connectedto said fluid motor for actuation thereby having means to directlytransmit motion of said fluid motor and resilient means for mechanicallystoring energy upon motion thereof by said fluid motor, means forhydraulically producing pressure operably connected to said mechanicalmeans for actuation thereby and hydraulically connected to saidhydraulic actuating means of said flow'reversing means, fluid throttlecontrol means in said last mentioned hydraulic connection to regulatethe rate of transfer 01' fluid from said means for producing hydraulicpressure to said hydraulic actuating means of said flow reversing meanswhereby actuation of said .mechanical means by said fluid motor at arate greater than that by which fluid can be displaced from the meansproducing hydraulic pressure through said throttle control means asactuated thereby causes said resilient means to store energymechanically to continue transfer of fluid from said means producinghydraulic pressure to said hydraulic actuating means for said flowreversing means and shift the same through neutral position to reverseflow position after actuation of said mechanical means has stopped andenergy is released by said resilient means, and means hydraulicallyconnecting said means for producing hydraulic pressure with themechanically. actuated means operably connected to said fluid motor foractuation thereby having means to directly transmit motion of said fluidmotor and resilient means for mechanically storing energy upon motionthereof by said .fluid motor, means for hydraulically producing pressureoperably connected to said mechanical means for actuation thereby andhydraulically connected to said hydraulic actuating means of said flowreversing means, fluid throttle control means in said last mentionedhydraulic connection to regulate the rate of transfer of fluid from saidmeans ,for producing hydraulic pressure to said hydraulic actuatingmeans of said flow reversing means whereby actuation of said mechanicalmeans by said fluid motor at a rate greater than that by which fluid canbe displaced from the means producing hydraulic pressure through saidthrottle control means causes said resilient means to store energymechanically to continue transfer of fluid from said means producinghydraulic pressure to said hydraulic actuating means for said flowreversing means and shift the same through neutral position to reverseflow, position after actuation of said mechanical discharge side of saidsource after shifting thereof by saidmechanical means whereby to, retainsaid means for producing hydraulic pressure in position to retain .saidflow reversing means in position to maintain the flow of fluid from saidsource in said reversed direction.

5. A fluid flow controlling apparatus in a hydraulic actuating systemthat includes, means providing a source of fluid under pressure foractuating a fluid motor operably connected therewith and' includingmeans reversing the direction of flow of fluid under pressure betweenthe source and the fluid motor having means for normally positioningsaid flow reversing means in one of two positions to normally cause saidsource to deliver in one direction and hydraulically actuated meansopposing the same to shift the flow reversing means through a neutral ormeans has stopped and energy is released by said resilient means, meanshydraulically con,- meeting said means for' producing hydraulic pressurewith the discharge side of said source after shifting thereof bysaidmechanical means whereby to retain said means for producing hydraulic pressure in position to retain said flow reversing means inposition to maintain the flow of fluid from said source in said reverseddirection, and means operably connected to said fluid motor and actuatedthereby for releasing pressure from said last mentioned hydraulicconnection upon a predetermined stroke of said fluid motor whereby topermit said flow reversing means to shift delivery from said source tosaid first mentioned normal direction of delivery,

therefrom.

6. lin a fluid flow controlling apparatus, a source of fluid pressure, areversible motor, hydraulic connections between said source and saidmotor including control means movable from a first position causingoperation of said motor in one direction,'through neutral, to a secondposition causing operation of said motor in the opposite direction,yielding means urging said control means into said first position,pressure responsive means operable to move said control means into saidsecond position, fluid pressure generating means movable between firstand second positions and hydraulically connected to operate saidpressure responsive means, means mechanically operated by said motor inone position, including energy storing means for urging said generatingmeans from first to second positions causing movement of said controlmeans intosaid second position, pressure connections from said controlmeans, operable to maintain said generating means in its said secondposition, and means operated by said motor in a second position to ventsaid pressure connections whereby said yielding means efiects a reversalof fluid flow to said motor.

7. In a fluid "flow controlling apparatus, a source of fluid pressure, areversible motor, hydraulic connections between said source and saidmotor including control means movable from a first position causingoperation of said motor in one direction, through neutral, to a secondposition causing operation of said motor in a reverse direction,yielding means urging said control means into said first position, forcetransmitting means operable from a first to a second position to movesaid control means into said second position, means operated by saidmotor in one position, including energy storing means for urging saidtransmitting means into said second position, a pressure connection fromsaid source operable to maintain said force transmitting means in saidsecond position, and means operated by said motor in a second positionto vent said connection and permit said'yielding means to return saidcontrol means to first position.

JOHAN A. MULLER.

WARREN R. TUCKER.

REFERENCES CITED file of this patent:

UNITED STATES PATENTS Number Name Date 153,784 Rickert Aug. 4, 1874260,398 Jenkins July 4, 1882 -'I1'I,136. Thomas Dec. 30, 1902 2,110,593Ernst Mar. 8, 1938 2,139,101 Spencer Dec. 6, 1938 2,192,778 Stacy Mar.5, 1940 2,363,760 Waldie Nov. 28, 1944 2,366,388 Crosby Jan. 2, 19452,391,996 Muller Jan. 1, 1946 FOREIGN PATENTS Number Country Date 14,135Great Britain 1884 OTHER REFERENCES Ser. No; 400,816, Lang (A. P. 0.),published Apr. 20, 1943.

